2-(1-Hydroxypentyl)-benzoate (dl-PHPB), a derivate of 3-n-butylphthalide (dl-NBP), is a novel drug candidate used for treatment of cerebral ischemia. The goal of the present study was to investigate the effects of dl-PHPB on infarct volume, neurological function, and cerebral blood flow (CBF) in transient focal cerebral ischemia. Therefore, an animal model of 2-h middle cerebral artery occlusion (MCAO) followed by 24-h reperfusion was used. Rats received dl-PHPB (1.3, 3.9, or 12.9 mg/kg) intravenously 10 min after the onset of MCAO. Compared with the vehicle control group (37.4%), infarct volume in dl-PHPB-treated groups was reduced significantly and dose-dependently to 25.4, 17.4, and 13.7%, respectively. The changes in neurological deficient were also observed in neurobehavioral test in a dose-dependent manner, and the neuronal score was improved significantly from the vehicle control of 3.2 to 2.7, 2.1, and 1.8, respectively. At the highest dose, the potency of dl-PHPB was similar to those of dl-NBP. CBF was quantified by using laser-Doppler flowmetry. During the ischemia, the regional CBF values of dl-PHPB groups were significantly higher than that of vehicle group. In addition, our study showed that dl-PHPB converted into dl-NBP very quickly in blood in vitro. Approximately 70% of dl-PHPB converted into dl-NBP in 5 min when dl-PHPB was added into plasma at final concentrations of 6, 30, and 60 mug/ml. This result demonstrated that the neuronal protection effects of dl-PHPB were mainly induced by dl-NBP, an active compound converted from its precursor, dl-PHPB. In conclusion, dl-PHPB can reduce infarct volume and improve neurobehavioral deficits in a rat model of transient MCAO. Those effects may partially be due to an increase in CBF by the active metabolite (dl-NBP) of dl-PHPB. Therefore, our results suggest that dl-PHPB may be useful for treatment of ischemia stroke.